1. Field of Invention
The present invention relates to a pump.
2. Related Prior Art
Taiwanese Patent Publication No. 228258 discloses a pump including a cylinder 10 and a nozzle 40 connected with the cylinder 10 by threading. That is, a thread 11 must be formed on an internal side of the cylinder 10, and a thread 41 must be formed on an external side of the nozzle 40. It is time-consuming to form the threads 11 and 41. The cylinder 10 is made of light but weak aluminum. The thread 11 is formed via tapering. Therefore, the cylinder 10 must be adequately thick in order to exhibit a sufficient strength after the tapering. The thicker the cylinder 10 is, the more aluminum is required to make the cylinder 10. This entails a high cost in manufacturing the cylinder 10. In addition, air tends to leak between the threads 11 and 41.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.